Our interest is to understand how genetically-identified cell types and their projections drive behaviors essential for survival. Using the mouse as our model system, we apply optogenetics and chemogenetics to manipulate neuronal circuits in awake, behaving mice. In addition, we use a combination of electrophysiology, two-photon fluorescence endomicroscopy, and behavioral assays to elucidate the neuronal basis of survival behaviors, such as feeding, and to determine how these neuronal circuits drive the rewarding and addictive nature of food intake. Evidence for the addictive properties of food has been growing progressively throughout the last decade. Both addiction and overeating are disorders by which individuals learn rewarding associations between stimuli such as drugs of abuse and highly palatable food. Therefore, our laboratory is interested in understanding the addictiveness aspects of feeding behaviors. We study this topic at the level of neuronal circuits in the context of behaviors, cell types, and synaptic connectivity. Neuronal circuits are composed of diverse collections of cell types, each having a distinct set of synaptic connections and performing specific functions. To understand how neuronal circuits drive behaviors, it is essential to examine the function of specific cell types in the circuit. However, studies have been mostly unable to identify the cell types involved in specific behaviors. Furthermore, experiments to date have largely been unable to determine when specific cell types are active to provide quantitative relationships between circuit activity and behavior. Ultimately, understanding the mechanisms regulating food intake and the rewarding and addictive nature of food will enhance our ability to battle disorders such as obesity, diabetes, anorexia, bulimia, and addiction.